1. Field of the Invention
This invention relates to the oxygenation and temperature adjustment of blood during medical procedures. More particularly, the invention concerns a disposable, one-use novel blood oxygenator with integrated stages for (1) oxygenating and heat exchanging and (2) defoaming and degassing the blood during treatment.
2. Description of Prior Art
In many medical procedures, the patient during an operation, is subject to blood treatment in a bypass flow outside of his body. The blood treatment includes oxygenation and temperature adjustment in an apparatus that may be termed as a "blood oxygenator".
This device has several important functions which include; (1) cooling the blood in the early portion of an operation, (2) dissolving oxygen into the blood, (3) removing all free oxygen bubbles and foam from the blood before its return to the patient, and (4) warming the blood to heat the patient in the latter portion of the operation so that the surgeon can close the wound.
The cooling and heating of human blood is confined to certain limits which must not be exceeded. For example, the lower temperature limit is where tissue damage occurs by freezing water. The upper temperature limit is 42 degrees centigrade, which limit if exceeded causes degradation of the blood.
In addition, the medical profession has turned increasingly to one-use disposable blood oxygenators which are ready to use in sterile packages since post operative clean-up and sterilization is hazardous if improper but expensive to do correctly.
Disposable blood oxygenators have been made for one-time use and also, fabricated from transparent plastic members so that their functioning is readily verified visually. In addition, the device must be relatively low cost for one time use but yet must perform perfectly in use since a patients well being is at risk of a malfunction.
U.S. Pat. Nos. 3,768,977, 3,769,162, 3,807,958, 4,138,288 and 4,138,464 show blood oxygenators of the prior art. The blood oxygenators shown in these patents have been used by the medical profession but their construction and assembly are complex and therefore expensive. In these devices, the oxygenating and heat exchanging stage is separated from a defoaming and degassing stage.
Attempts have been made to improve the oxygenating and heat exchanging stage as shown in U.S. Pat. Nos. 3,870,470 and 3,994,689. In these patents, this stage is of a design to simplify construction while trying to combine the oxygenating and heat exchanging functions by common wall elements. However, these devices are structurally too large when capable of producing the proper treatment of blood.
The present invention in a blood oxygenator has all of the desired characteristics in a one-use and discard transparent device. The device has a construction permitting an "insert" type of assembly of all operative internal elements into a vessel which is then sealed at the top by a cover that includes the remainder of the elements. In addition, the device is more compact and performs blood treatment as to oxygenating, heat exchanging, degassing and defoaming in a better improved manner than the prior art blood oxygenators.